The present invention generally relates to printers in facsimile machines and, more particularly, to the apparatus for mounting print cartridges in these printers for facsimile printing.
The general design and construction of carriages that retain and align print cartridges in printers and scan these print cartridges through print zones is well known. Examples of the patents that have issued in the field of ink jet printing technology include:
U.S. Pat. No. 4,755,836 entitled xe2x80x9cPrinthead Cartridge and Carriage Assemblyxe2x80x9d by Ta et al. issued Jul. 5, 1988;
U.S. Pat. No. 4,872,026 entitled xe2x80x9cInk-jet Printer with Printhead Carriage Alignment Mechanismxe2x80x9d by Rasmussen et al. issued Oct. 3, 1989;
U.S. Pat. No. 4,907,018 entitled xe2x80x9cPrinthead-Carriage Alignment and Electrical Interconnect Lock-in Mechanismxe2x80x9d by Pinkerpell issued Mar. 6, 1990; and
U.S. Pat. No. 5,392,063 entitled xe2x80x9cSpring Cartridge Clamp for Inkjet Printer Carriagexe2x80x9d by Rhoads issued Feb. 21, 1995.
Prior facsimile machines have proven to be quite satisfactory; however it is believed that facsimile users want a facsimile machine with a smaller profile. In other words, users wish to reproduce all of the currently available facsimile functions in a product of reduced size. This desire has resulted in a need for a smaller printer and with it, a smaller carriage.
Such requirements result in numerous design challenges. First, the forces that a user must exert for the insertion and removal of a print cartridge from a carriage must be kept within an acceptable range, that is to say, to be as small and as comfortable as possible. Second, since the height of the carriage is less, the mechanical moment arm between the datums on the print cartridge and the latch spring is less. More specifically, they are closer together during loading, operating, and unloading. Third, the latch on the present print cartridge is located behind the margin of the print cartridge where in prior cartridges the latch was located at the margin. This positioning reduces the mechanical moment arm even further. Thus, to achieve the same insertion and removal force as is present on larger, prior carriages, the force exerted by the latch spring must be increased. Prior solutions would have made the latch spring stouter, but as a spring gets thicker, it will not bend as far and still spring back. In addition, increasing the size of the latch spring is undesirable because the space available for the spring has been substantially reduced.
Thus, it is apparent from the foregoing that although there arc many different latch spring designs for the carriages in facsimile machines, designing a latch spring for a low height facsimile printer presents many challenges.
Briefly and in general terms, an apparatus according to the invention includes a cantilever spring having a free end and an anchorable end. The spring is doubled back on itself to obtain a long effective length in a short space.
Other aspects and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.